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<FONT color="green">001</FONT>    <a name="line.1"></a>
<FONT color="green">002</FONT>    /*<a name="line.2"></a>
<FONT color="green">003</FONT>     * Copyright (C) 2011 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<FONT color="green">004</FONT>     *<a name="line.4"></a>
<FONT color="green">005</FONT>     * $Id: IPv4Util.html 4 2011-02-05 22:22:47Z archie.cobbs $<a name="line.5"></a>
<FONT color="green">006</FONT>     */<a name="line.6"></a>
<FONT color="green">007</FONT>    <a name="line.7"></a>
<FONT color="green">008</FONT>    package org.dellroad.stuff.net;<a name="line.8"></a>
<FONT color="green">009</FONT>    <a name="line.9"></a>
<FONT color="green">010</FONT>    import java.net.Inet4Address;<a name="line.10"></a>
<FONT color="green">011</FONT>    import java.net.InetAddress;<a name="line.11"></a>
<FONT color="green">012</FONT>    import java.net.UnknownHostException;<a name="line.12"></a>
<FONT color="green">013</FONT>    import java.util.regex.Matcher;<a name="line.13"></a>
<FONT color="green">014</FONT>    import java.util.regex.Pattern;<a name="line.14"></a>
<FONT color="green">015</FONT>    <a name="line.15"></a>
<FONT color="green">016</FONT>    /**<a name="line.16"></a>
<FONT color="green">017</FONT>     * Utility methods for working with IPv4 addresses and netmasks.<a name="line.17"></a>
<FONT color="green">018</FONT>     */<a name="line.18"></a>
<FONT color="green">019</FONT>    public final class IPv4Util {<a name="line.19"></a>
<FONT color="green">020</FONT>    <a name="line.20"></a>
<FONT color="green">021</FONT>        public static final int MIN_VALID_NETMASK_WIDTH = 8;<a name="line.21"></a>
<FONT color="green">022</FONT>        public static final int MAX_VALID_NETMASK_WIDTH = 30;<a name="line.22"></a>
<FONT color="green">023</FONT>    <a name="line.23"></a>
<FONT color="green">024</FONT>        private IPv4Util() {<a name="line.24"></a>
<FONT color="green">025</FONT>        }<a name="line.25"></a>
<FONT color="green">026</FONT>    <a name="line.26"></a>
<FONT color="green">027</FONT>        /**<a name="line.27"></a>
<FONT color="green">028</FONT>         * Convert from 32-bit integer representation.<a name="line.28"></a>
<FONT color="green">029</FONT>         */<a name="line.29"></a>
<FONT color="green">030</FONT>        public static Inet4Address toAddress(int address) {<a name="line.30"></a>
<FONT color="green">031</FONT>            return IPv4Util.toAddress(new byte[] {<a name="line.31"></a>
<FONT color="green">032</FONT>                (byte)((address &gt;&gt; 24) &amp; 0xff),<a name="line.32"></a>
<FONT color="green">033</FONT>                (byte)((address &gt;&gt; 16) &amp; 0xff),<a name="line.33"></a>
<FONT color="green">034</FONT>                (byte)((address &gt;&gt; 8) &amp; 0xff),<a name="line.34"></a>
<FONT color="green">035</FONT>                (byte)(address &amp; 0xff),<a name="line.35"></a>
<FONT color="green">036</FONT>            });<a name="line.36"></a>
<FONT color="green">037</FONT>        }<a name="line.37"></a>
<FONT color="green">038</FONT>    <a name="line.38"></a>
<FONT color="green">039</FONT>        /**<a name="line.39"></a>
<FONT color="green">040</FONT>         * Convert to 32-bit integer representation.<a name="line.40"></a>
<FONT color="green">041</FONT>         */<a name="line.41"></a>
<FONT color="green">042</FONT>        public static int toInt32(Inet4Address address) {<a name="line.42"></a>
<FONT color="green">043</FONT>            byte[] bytes = address.getAddress();<a name="line.43"></a>
<FONT color="green">044</FONT>            return ((bytes[0] &amp; 0xff) &lt;&lt; 24)<a name="line.44"></a>
<FONT color="green">045</FONT>                 | ((bytes[1] &amp; 0xff) &lt;&lt; 16)<a name="line.45"></a>
<FONT color="green">046</FONT>                 | ((bytes[2] &amp; 0xff) &lt;&lt; 8)<a name="line.46"></a>
<FONT color="green">047</FONT>                 | (bytes[3] &amp; 0xff);<a name="line.47"></a>
<FONT color="green">048</FONT>        }<a name="line.48"></a>
<FONT color="green">049</FONT>    <a name="line.49"></a>
<FONT color="green">050</FONT>        /**<a name="line.50"></a>
<FONT color="green">051</FONT>         * Convert to an unsigned 32-bit integer representation within a 64-bit long.<a name="line.51"></a>
<FONT color="green">052</FONT>         */<a name="line.52"></a>
<FONT color="green">053</FONT>        public static long toUInt32(Inet4Address address) {<a name="line.53"></a>
<FONT color="green">054</FONT>            return toInt32(address) &amp; 0x00000000ffffffffL;<a name="line.54"></a>
<FONT color="green">055</FONT>        }<a name="line.55"></a>
<FONT color="green">056</FONT>    <a name="line.56"></a>
<FONT color="green">057</FONT>        /**<a name="line.57"></a>
<FONT color="green">058</FONT>         * Convert raw bytes to an {@link Inet4Address}.<a name="line.58"></a>
<FONT color="green">059</FONT>         *<a name="line.59"></a>
<FONT color="green">060</FONT>         * @throws IllegalArgumentException if array does not have length four<a name="line.60"></a>
<FONT color="green">061</FONT>         */<a name="line.61"></a>
<FONT color="green">062</FONT>        public static Inet4Address toAddress(byte[] bytes) {<a name="line.62"></a>
<FONT color="green">063</FONT>            if (bytes.length != 4)<a name="line.63"></a>
<FONT color="green">064</FONT>                throw new IllegalArgumentException("array has length " + bytes.length + " != 4");<a name="line.64"></a>
<FONT color="green">065</FONT>            try {<a name="line.65"></a>
<FONT color="green">066</FONT>                return (Inet4Address)InetAddress.getByAddress(toString(bytes), bytes);<a name="line.66"></a>
<FONT color="green">067</FONT>            } catch (UnknownHostException e) {<a name="line.67"></a>
<FONT color="green">068</FONT>                throw new RuntimeException("unexpected exception", e);<a name="line.68"></a>
<FONT color="green">069</FONT>            }<a name="line.69"></a>
<FONT color="green">070</FONT>        }<a name="line.70"></a>
<FONT color="green">071</FONT>    <a name="line.71"></a>
<FONT color="green">072</FONT>        /**<a name="line.72"></a>
<FONT color="green">073</FONT>         * Convert an IPv4 address to string representation.<a name="line.73"></a>
<FONT color="green">074</FONT>         *<a name="line.74"></a>
<FONT color="green">075</FONT>         * @throws IllegalArgumentException if array does not have length four<a name="line.75"></a>
<FONT color="green">076</FONT>         */<a name="line.76"></a>
<FONT color="green">077</FONT>        public static String toString(Inet4Address address) {<a name="line.77"></a>
<FONT color="green">078</FONT>            return IPv4Util.toString(address.getAddress());<a name="line.78"></a>
<FONT color="green">079</FONT>        }<a name="line.79"></a>
<FONT color="green">080</FONT>    <a name="line.80"></a>
<FONT color="green">081</FONT>        /**<a name="line.81"></a>
<FONT color="green">082</FONT>         * Convert a network address (IPv4 base address and netmask) to string representation.<a name="line.82"></a>
<FONT color="green">083</FONT>         *<a name="line.83"></a>
<FONT color="green">084</FONT>         * @throws IllegalArgumentException if array does not have length four<a name="line.84"></a>
<FONT color="green">085</FONT>         */<a name="line.85"></a>
<FONT color="green">086</FONT>        public static String toString(Inet4Address address, Inet4Address netmask) {<a name="line.86"></a>
<FONT color="green">087</FONT>            return IPv4Util.toString(address) + "/" + IPv4Util.getWidth(netmask);<a name="line.87"></a>
<FONT color="green">088</FONT>        }<a name="line.88"></a>
<FONT color="green">089</FONT>    <a name="line.89"></a>
<FONT color="green">090</FONT>        private static String toString(byte[] bytes) {<a name="line.90"></a>
<FONT color="green">091</FONT>            assert bytes.length == 4;<a name="line.91"></a>
<FONT color="green">092</FONT>            return (bytes[0] &amp; 0xff) + "." + (bytes[1] &amp; 0xff) + "." + (bytes[2] &amp; 0xff) + "." + (bytes[3] &amp; 0xff);<a name="line.92"></a>
<FONT color="green">093</FONT>        }<a name="line.93"></a>
<FONT color="green">094</FONT>    <a name="line.94"></a>
<FONT color="green">095</FONT>        /**<a name="line.95"></a>
<FONT color="green">096</FONT>         * Convert from string representation.<a name="line.96"></a>
<FONT color="green">097</FONT>         *<a name="line.97"></a>
<FONT color="green">098</FONT>         * @throws IllegalArgumentException if string is not an IP address<a name="line.98"></a>
<FONT color="green">099</FONT>         */<a name="line.99"></a>
<FONT color="green">100</FONT>        public static Inet4Address fromString(String string) {<a name="line.100"></a>
<FONT color="green">101</FONT>            String bytepat = "([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])";<a name="line.101"></a>
<FONT color="green">102</FONT>            Pattern pattern = Pattern.compile(bytepat + "\\." + bytepat + "\\." + bytepat + "\\." + bytepat);<a name="line.102"></a>
<FONT color="green">103</FONT>            Matcher matcher = pattern.matcher(string);<a name="line.103"></a>
<FONT color="green">104</FONT>            if (!matcher.matches())<a name="line.104"></a>
<FONT color="green">105</FONT>                throw new IllegalArgumentException("invalid IP address: " + string);<a name="line.105"></a>
<FONT color="green">106</FONT>            return toAddress(new byte[] {<a name="line.106"></a>
<FONT color="green">107</FONT>              (byte)Integer.parseInt(matcher.group(1)),<a name="line.107"></a>
<FONT color="green">108</FONT>              (byte)Integer.parseInt(matcher.group(2)),<a name="line.108"></a>
<FONT color="green">109</FONT>              (byte)Integer.parseInt(matcher.group(3)),<a name="line.109"></a>
<FONT color="green">110</FONT>              (byte)Integer.parseInt(matcher.group(4))<a name="line.110"></a>
<FONT color="green">111</FONT>            });<a name="line.111"></a>
<FONT color="green">112</FONT>        }<a name="line.112"></a>
<FONT color="green">113</FONT>    <a name="line.113"></a>
<FONT color="green">114</FONT>        /**<a name="line.114"></a>
<FONT color="green">115</FONT>         * Get netmask width.<a name="line.115"></a>
<FONT color="green">116</FONT>         *<a name="line.116"></a>
<FONT color="green">117</FONT>         * @return a value between zero and 32 (inclusive)<a name="line.117"></a>
<FONT color="green">118</FONT>         * @throws IllegalArgumentException if the value is not a valid CIDR netmask<a name="line.118"></a>
<FONT color="green">119</FONT>         */<a name="line.119"></a>
<FONT color="green">120</FONT>        public static int getWidth(Inet4Address netmask) {<a name="line.120"></a>
<FONT color="green">121</FONT>            int mask = toInt32(netmask);<a name="line.121"></a>
<FONT color="green">122</FONT>            if (mask == 0)<a name="line.122"></a>
<FONT color="green">123</FONT>                return 0;<a name="line.123"></a>
<FONT color="green">124</FONT>            for (int shift = 0; shift &lt; 32; shift++) {<a name="line.124"></a>
<FONT color="green">125</FONT>                if (mask == (~0 &lt;&lt; shift))<a name="line.125"></a>
<FONT color="green">126</FONT>                    return 32 - shift;<a name="line.126"></a>
<FONT color="green">127</FONT>            }<a name="line.127"></a>
<FONT color="green">128</FONT>            throw new IllegalArgumentException("invalid netmask " + netmask);<a name="line.128"></a>
<FONT color="green">129</FONT>        }<a name="line.129"></a>
<FONT color="green">130</FONT>    <a name="line.130"></a>
<FONT color="green">131</FONT>        /**<a name="line.131"></a>
<FONT color="green">132</FONT>         * Determine if the given address is a valid CIDR netmask.<a name="line.132"></a>
<FONT color="green">133</FONT>         * The netmask must have a width between 8 and 30 (inclusive).<a name="line.133"></a>
<FONT color="green">134</FONT>         */<a name="line.134"></a>
<FONT color="green">135</FONT>        public static boolean isValidNetmask(Inet4Address netmask) {<a name="line.135"></a>
<FONT color="green">136</FONT>            try {<a name="line.136"></a>
<FONT color="green">137</FONT>                int width = getWidth(netmask);<a name="line.137"></a>
<FONT color="green">138</FONT>                return width &gt;= MIN_VALID_NETMASK_WIDTH &amp;&amp; width &lt;= MAX_VALID_NETMASK_WIDTH;<a name="line.138"></a>
<FONT color="green">139</FONT>            } catch (IllegalArgumentException e) {<a name="line.139"></a>
<FONT color="green">140</FONT>                return false;<a name="line.140"></a>
<FONT color="green">141</FONT>            }<a name="line.141"></a>
<FONT color="green">142</FONT>        }<a name="line.142"></a>
<FONT color="green">143</FONT>    <a name="line.143"></a>
<FONT color="green">144</FONT>        /**<a name="line.144"></a>
<FONT color="green">145</FONT>         * Get netmask with the given width.<a name="line.145"></a>
<FONT color="green">146</FONT>         *<a name="line.146"></a>
<FONT color="green">147</FONT>         * @throws IllegalArgumentException if width is less than zero or greater than 32<a name="line.147"></a>
<FONT color="green">148</FONT>         */<a name="line.148"></a>
<FONT color="green">149</FONT>        public static Inet4Address getNetmaskForWidth(int width) {<a name="line.149"></a>
<FONT color="green">150</FONT>            if (width &lt; 0 || width &gt; 32)<a name="line.150"></a>
<FONT color="green">151</FONT>                throw new IllegalArgumentException("invalid netmask width " + width);<a name="line.151"></a>
<FONT color="green">152</FONT>            return toAddress(~0 &lt;&lt; (32 - width));<a name="line.152"></a>
<FONT color="green">153</FONT>        }<a name="line.153"></a>
<FONT color="green">154</FONT>    <a name="line.154"></a>
<FONT color="green">155</FONT>        /**<a name="line.155"></a>
<FONT color="green">156</FONT>         * Get the base address (all host bits zero) of the given IP network.<a name="line.156"></a>
<FONT color="green">157</FONT>         *<a name="line.157"></a>
<FONT color="green">158</FONT>         * @param address any IP address on the network<a name="line.158"></a>
<FONT color="green">159</FONT>         * @param netmask the netmask of the network<a name="line.159"></a>
<FONT color="green">160</FONT>         * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.160"></a>
<FONT color="green">161</FONT>         */<a name="line.161"></a>
<FONT color="green">162</FONT>        public static Inet4Address getBaseAddress(Inet4Address address, Inet4Address netmask) {<a name="line.162"></a>
<FONT color="green">163</FONT>            int addr = toInt32(address);<a name="line.163"></a>
<FONT color="green">164</FONT>            int width = getWidth(netmask);<a name="line.164"></a>
<FONT color="green">165</FONT>            addr &amp;= ~0 &lt;&lt; (32 - width);<a name="line.165"></a>
<FONT color="green">166</FONT>            return toAddress(addr);<a name="line.166"></a>
<FONT color="green">167</FONT>        }<a name="line.167"></a>
<FONT color="green">168</FONT>    <a name="line.168"></a>
<FONT color="green">169</FONT>        /**<a name="line.169"></a>
<FONT color="green">170</FONT>         * Get the broadcast address (all host bits one) of the given IP network.<a name="line.170"></a>
<FONT color="green">171</FONT>         *<a name="line.171"></a>
<FONT color="green">172</FONT>         * @param address any IP address on the network<a name="line.172"></a>
<FONT color="green">173</FONT>         * @param netmask the netmask of the network<a name="line.173"></a>
<FONT color="green">174</FONT>         * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.174"></a>
<FONT color="green">175</FONT>         */<a name="line.175"></a>
<FONT color="green">176</FONT>        public static Inet4Address getBroadcastAddress(Inet4Address address, Inet4Address netmask) {<a name="line.176"></a>
<FONT color="green">177</FONT>            int addr = toInt32(address);<a name="line.177"></a>
<FONT color="green">178</FONT>            int width = getWidth(netmask);<a name="line.178"></a>
<FONT color="green">179</FONT>            addr |= ~(~0 &lt;&lt; (32 - width));<a name="line.179"></a>
<FONT color="green">180</FONT>            return toAddress(addr);<a name="line.180"></a>
<FONT color="green">181</FONT>        }<a name="line.181"></a>
<FONT color="green">182</FONT>    <a name="line.182"></a>
<FONT color="green">183</FONT>        /**<a name="line.183"></a>
<FONT color="green">184</FONT>         * Determine if the given address lives on the given network.<a name="line.184"></a>
<FONT color="green">185</FONT>         *<a name="line.185"></a>
<FONT color="green">186</FONT>         * @param address IP address in question<a name="line.186"></a>
<FONT color="green">187</FONT>         * @param network network address<a name="line.187"></a>
<FONT color="green">188</FONT>         * @param netmask network netmask<a name="line.188"></a>
<FONT color="green">189</FONT>         * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.189"></a>
<FONT color="green">190</FONT>         */<a name="line.190"></a>
<FONT color="green">191</FONT>        public static boolean isOnNetwork(Inet4Address address, Inet4Address network, Inet4Address netmask) {<a name="line.191"></a>
<FONT color="green">192</FONT>            int addr1 = toInt32(address);<a name="line.192"></a>
<FONT color="green">193</FONT>            int addr2 = toInt32(network);<a name="line.193"></a>
<FONT color="green">194</FONT>            int width = getWidth(netmask);<a name="line.194"></a>
<FONT color="green">195</FONT>            int mask = ~0 &lt;&lt; (32 - width);<a name="line.195"></a>
<FONT color="green">196</FONT>            return (addr1 &amp; mask) == (addr2 &amp; mask);<a name="line.196"></a>
<FONT color="green">197</FONT>        }<a name="line.197"></a>
<FONT color="green">198</FONT>    <a name="line.198"></a>
<FONT color="green">199</FONT>        /**<a name="line.199"></a>
<FONT color="green">200</FONT>         * Determine if the given address is a valid host address on the given network.<a name="line.200"></a>
<FONT color="green">201</FONT>         * The address must lie on the given network and not equal either the base or broadcast addresses.<a name="line.201"></a>
<FONT color="green">202</FONT>         *<a name="line.202"></a>
<FONT color="green">203</FONT>         * @param address IP address in question<a name="line.203"></a>
<FONT color="green">204</FONT>         * @param network network address<a name="line.204"></a>
<FONT color="green">205</FONT>         * @param netmask network netmask<a name="line.205"></a>
<FONT color="green">206</FONT>         * @throws IllegalArgumentException if {@code netmask} is not a valid netmask<a name="line.206"></a>
<FONT color="green">207</FONT>         */<a name="line.207"></a>
<FONT color="green">208</FONT>        public static boolean isValidHostOnNetwork(Inet4Address address, Inet4Address network, Inet4Address netmask) {<a name="line.208"></a>
<FONT color="green">209</FONT>            return isOnNetwork(address, network, netmask)<a name="line.209"></a>
<FONT color="green">210</FONT>             &amp;&amp; !address.equals(getBaseAddress(network, netmask))<a name="line.210"></a>
<FONT color="green">211</FONT>             &amp;&amp; !address.equals(getBroadcastAddress(network, netmask));<a name="line.211"></a>
<FONT color="green">212</FONT>        }<a name="line.212"></a>
<FONT color="green">213</FONT>    }<a name="line.213"></a>
<FONT color="green">214</FONT>    <a name="line.214"></a>




























































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